Ballcock valves of the type commonly used in commode water tanks regularly utilize a float to establish the water level to which the tank is to be filled. The float enables the valve to open to refil the tank when the float is at some lower elevation, and causes the valve to shut off when the float rises to a predetermined elevation. This elevation is directly related to the desired water level.
The most commonly used float in the United States has the float pivotally mounted to the valve. This arrangement is widely used when the buoyant force of the float exerts a closing force on a valving element.
Another type of ballcock valve utilizes a differential pressure system, and the float merely opens or closes a pilot port. This arrangement enables a simpler and less expensive float system to be used, because it can be made without an intervening linkage between the float and the valve. In fact, it is commonly provided as an inverted cup, whose buoyancy is derived from air trapped in the cup by the rising water. The problem is in the adjustment of the cup relative to the valve so the water level can be adjusted. One way, of course, is to slidably mount the cup onto structure which itself moves relative to the valve. An example of workings useful with such a float is shown in Heyer et al U.S. Pat. No. 3,618,629.
The marketing of ballcock valves for toilet use is highly competitive, and anything which adds expense is a severe detriment to the manufacturer. It is an object of this invention to provide an inverted cup float which is inherently adjustable to determine the water level at which it becomes buoyant and shuts off the valve, without requiring any intervening structure, or sliding movement of the float for purposes of adjustment of the water level. As such its cost is minimized while it performs the same function relative to the valve as the known more complicated and expensive systems do.